Effect of CeO2 on density and wear resistance of Ni-Cr-WC coatings by theoretical calculation and experimental investigation

Abstract

Abstract The differential charge density and density of states used to analyze the bonding of atoms at the interface, the interface adhesion and spreading coefficient of the interface were calculated by first principle method. Ni-Cr-WC and Ni-Cr-WC-CeO2 wear resistant coatings were prepared by sintering method. The density of the coatings was measured. The morphology and elemental distribution of the coatings were observed and analyzed by the scanning electron microscope. The wear scratch morphology was observed and measured by the white confocal microscope, and the wear volume was fitted. The results of differential charge density and density of states show that there are polar covalent bonds and metal bonds at the Ni/CeO2 interface, so the wetting tendency of Ni and CeO2 is poor. The interfacial adhesion work is −1.63 ev/A2, and the spreading factor is 14.63 ev/A2. It indicates that Ni atoms could not spontaneously wet on the surface of CeO2, which can improve the density of the Ni-base coating. The experimental results show that CeO2 is distributed in the matrix of the coating. The large pores in the coating disappear, and the density of the coatings is increased from 99.89% to 99.92%. The wear volume of the coating is decreased from 14.56\u202f×\u202f106\u202fμm3 to 7.31\u202f×\u202f106\u202fμm3, which indicates that the wear resistance of the coating with CeO2 is improved.